Honeycomb core sandwich panels
In accordance with one embodiment of the present disclosure, a method for manufacturing a honeycomb core sandwich panel includes placing a thermoset facesheet in contact with a thermoplastic honeycomb core without using a separate adhesive and attaching the thermoset facesheet to the thermoplastic honeycomb core by using a curing profile comprising a temperature that is lower than a gel point temperature of the thermoset facesheet and higher than a softening point temperature of the thermoplastic honeycomb core.
1. A method for manufacturing a honeycomb core sandwich panel, comprising:
placing a thermoset facesheet in contact with a thermoplastic honeycomb core without using a separate adhesive disposed between the thermoset facesheet and the thermoplastic honeycomb core; and
attaching the thermoset facesheet to the thermoplastic honeycomb core by using a curing profile comprising a temperature that is:
lower than a gel point temperature of the thermoset facesheet;
higher than a softening point temperature of the thermoplastic honeycomb core;
analyzing the thermoset facesheet to determine the gel point temperature of the thermoset facesheet;
analyzing the thermoplastic honeycomb core to determine the softening point temperature of the thermoplastic honeycomb core;
determining whether the thermoplastic honeycomb core and the thermoset facesheet each have a viscosity at the temperature suitable for mechanical interlocking of the thermoplastic honeycomb core and the thermoset facesheet;
determining the curing profile comprising the temperature; and
wherein using the curing profile comprises curing the thermoplastic facesheet and the thermoplastic honeycomb core at the same time and at the same temperature.
2. The method of claim 1 , wherein the thermoset facesheet comprises an epoxy resin.
3. The method of claim 1 , wherein the thermoplastic honeycomb core comprises polyetherimide (PEI).
4. The method of claim 1 , wherein:
the thermoset facesheet comprises an epoxy resin prepreg; and
the thermoplastic honeycomb core comprises polyetherimide (PEI).
5. The method of claim 1 , wherein the thermoplastic honeycomb core comprises a plurality of cells, each cell comprising a curved cell wall in a substantially circular tube shape, wherein:
measured at a midplane of each cell, the diameter of the substantially circular tube does not vary more than about 10 percent within the same cell.
6. The method of claim 1 , wherein, during curing:
the thermoset facesheet chemically interacts with the thermoplastic honeycomb core;
the thermoplastic honeycomb core deforms at a plurality of locations where the thermoplastic honeycomb core is in contact with the thermoset facesheet; and
the thermoset facesheet mechanically interlocks with the thermoplastic honeycomb core.
7. The method of claim 1 , wherein the curing occurs:
at a pressure less than ambient pressure for a certain period of time; and
in a vacuum-capable oven.
8. A method for manufacturing a honeycomb core sandwich panel, comprising:
placing a thermoset facesheet in contact with a thermoplastic honeycomb core; and
attaching the thermoset facesheet to the thermoplastic honeycomb core by using a curing profile comprising a temperature that is:
lower than a gel point temperature of the thermoset facesheet;
higher than a softening point temperature of the thermoplastic honeycomb core;
analyzing the thermoset facesheet to determine the gel point temperature of the thermoset facesheet;
analyzing the thermoplastic honeycomb core to determine the softening point temperature of the thermoplastic honeycomb core;
determining whether the thermoplastic honeycomb core and the thermoset facesheet each have a viscosity at the temperature suitable for mechanical interlocking of the thermoplastic honeycomb core and the thermoset facesheet;
determining the curing profile comprising the temperature; and
wherein using the curing profile comprises curing the thermoplastic facesheet and the thermoplastic honeycomb core at the same time and at the same temperature.
9. The method of claim 8 , wherein:
the thermoset facesheet comprises an epoxy resin; and
the thermoplastic honeycomb core comprises polyetherimide (PEI).
10. The method of claim 8 , wherein:
the thermoset facesheet comprises an epoxy resin prepreg; and
the thermoplastic honeycomb core comprises polyetherimide (PEI).
11. The method of claim 8 , wherein the thermoplastic honeycomb core comprises a plurality of cells, each cell comprising a curved cell wall in a substantially circular tube shape, wherein:
measured at a midplane of each cell, the diameter of the substantially circular tube does not vary more than about 10 percent within the same cell.
12. The method of claim 8 , wherein, during curing:
the thermoset facesheet chemically interacts with the thermoplastic honeycomb core;
the thermoplastic honeycomb core deforms at a plurality of locations where the thermoplastic honeycomb core is in contact with the thermoset facesheet; and
the thermoset facesheet mechanically interlocks with the thermoplastic honeycomb core.
13. The method of claim 8 , wherein the curing occurs:
at a pressure less than ambient pressure for a certain period of time; and
in a vacuum-capable oven.